Add an --immediate flag to cryfs-unmount that tries to unmount immediately and doesn't wait for processes to release their locks on the file system.

ChangeLog.txt

@@ -9,6 +9,7 @@ Other changes:
 
 New features:
 * Add support for atime mount options (noatime, strictatime, relatime, atime, nodiratime). As before, relatime is the default.
+* Add an --immediate flag to cryfs-unmount that tries to unmount immediately and doesn't wait for processes to release their locks on the file system.
 
 
 Version 0.10.3 (unreleased)

src/cryfs-unmount/Cli.cpp

@@ -25,12 +25,33 @@ void Cli::main(int argc, const char **argv) {
     if (!boost::filesystem::exists(options.mountDir())) {
         throw cryfs::CryfsException("Given mountdir doesn't exist", cryfs::ErrorCode::InaccessibleMountDir);
     }
+
+    bool immediate = options.immediate();
+#if defined(__APPLE__)
+    if (options.immediate()) {
+        std::cerr << "Warning: OSX doesn't support the --immediate flag. Ignoring it.";
+        immediate = false;
+    }
+#elif defined(_MSC_VER)
+    if (options.immediate()) {
+        std::cerr << "Warning: Windows doesn't support the --immediate flag. Ignoring it.";
+        immediate = false;
+    }
+#endif
+
     // TODO This doesn't seem to work with relative paths
     std::cout << "Unmounting CryFS filesystem at " << options.mountDir() << "." << std::endl;
-    Fuse::unmount(options.mountDir());
+    if (immediate) {
+        Fuse::unmount(options.mountDir(), true);
 
-    // TODO Wait until it is actually unmounted and then show a better success message?
-    std::cout << "Filesystem is unmounting now." << std::endl;
+        // TODO Wait until it is actually unmounted and then show a better success message?
+        std::cout << "Filesystem is unmounting." << std::endl;
+    } else {
+        Fuse::unmount(options.mountDir(), false);
+
+        // TODO Wait until it is actually unmounted and then show a better success message?
+        std::cout << "Filesystem will unmount as soon as nothing is accessing it anymore." << std::endl;
+    }
 }
 
 }

src/cryfs-unmount/program_options/Parser.cpp

@@ -36,8 +36,9 @@ ProgramOptions Parser::parse() const {
 		_showHelpAndExit("Please specify a mount directory.", ErrorCode::InvalidArguments);
 	}
 	bf::path mountDir = vm["mount-dir"].as<string>();
+	bool immediate = vm.count("immediate");
 
-	return ProgramOptions(std::move(mountDir));
+	return ProgramOptions(std::move(mountDir), immediate);
 }
 
 po::variables_map Parser::_parseOptionsOrShowHelp(const vector<string> &options) {
@@ -95,8 +96,9 @@ void Parser::_addAllowedOptions(po::options_description *desc) {
 	string blocksize_description = "The block size used when storing ciphertext blocks (in bytes). Default: ";
 	blocksize_description += std::to_string(CryConfigConsole::DEFAULT_BLOCKSIZE_BYTES);
 	options.add_options()
+		("immediate", "unmount immediately without waiting for processes that currently access the file system to finish their file system operations. With this flag, unmounting can fail if there's processes having a lock on the file system.")
 		("help,h", "show help message")
-		("version", "Show CryFS version number")
+		("version", "show CryFS version number")
 		;
 	desc->add(options);
 }

src/cryfs-unmount/program_options/ProgramOptions.cpp

@@ -7,19 +7,28 @@ using namespace cryfs_unmount::program_options;
 using std::string;
 namespace bf = boost::filesystem;
 
-ProgramOptions::ProgramOptions(bf::path mountDir)
-	:_mountDir(std::move(mountDir)),
-	 _mountDirIsDriveLetter(cpputils::path_is_just_drive_letter(_mountDir))
+ProgramOptions::ProgramOptions(bf::path mountDir, bool immediate)
+	: _mountDir(std::move(mountDir)),
+	  _mountDirIsDriveLetter(cpputils::path_is_just_drive_letter(_mountDir)),
+	  _immediate(immediate)
 {
-	if (!_mountDirIsDriveLetter) {
+	if (!_mountDirIsDriveLetter)
+	{
 		_mountDir = bf::absolute(std::move(_mountDir));
 	}
 }
 
-const bf::path &ProgramOptions::mountDir() const {
+const bf::path &ProgramOptions::mountDir() const
+{
 	return _mountDir;
 }
 
-bool ProgramOptions::mountDirIsDriveLetter() const {
+bool ProgramOptions::mountDirIsDriveLetter() const
+{
 	return _mountDirIsDriveLetter;
 }
+
+bool ProgramOptions::immediate() const
+{
+	return _immediate;
+}

src/cryfs-unmount/program_options/ProgramOptions.h

@@ -8,23 +8,28 @@
 #include <cpp-utils/macros.h>
 #include <boost/filesystem.hpp>
 
-namespace cryfs_unmount {
-	namespace program_options {
-		class ProgramOptions final {
+namespace cryfs_unmount
+{
+	namespace program_options
+	{
+		class ProgramOptions final
+		{
 		public:
-			ProgramOptions(boost::filesystem::path mountDir);
+			ProgramOptions(boost::filesystem::path mountDir, bool immediate);
 			ProgramOptions(ProgramOptions &&rhs) = default;
 
 			const boost::filesystem::path &mountDir() const;
 			bool mountDirIsDriveLetter() const;
+			bool immediate() const;
 
 		private:
 			boost::filesystem::path _mountDir;
 			bool _mountDirIsDriveLetter;
+			bool _immediate;
 
 			DISALLOW_COPY_AND_ASSIGN(ProgramOptions);
 		};
-	}
-}
+	} // namespace program_options
+} // namespace cryfs_unmount
 
 #endif